Being able to transfer batteries from low priority equipment to high priority can be invaluable. It means the luxury gadgets you carry can also be considered as spare battery holders for survival items. At one point I had electric shaver, electric toothbrush, and camera all running on AAs.

Picking AAs to standardise on brings further benefits, because they are so flexible. You can own a mix of alkaline, lithium and LSD rechargeable for different situations. In addition to having fewer batteries to "bring", you'll need fewer rechargers and cables, and you can keep a stockpile of rechargeables always charged up at home.